Massachusetts Mutual Life Insurance Company plans to invest $300 million to expand its footprint in its home state of Massachusetts. That includes significantly increasing its presence in Springfield, and growing its operations in Boston.

The company will construct a roughly $240-million new campus in Boston’s Seaport district on Fan Pier by 2021. The 300,000-square-foot, multi-story office development on the South Boston waterfront will ultimately house roughly 1,000 employees. The facility, on an undeveloped parcel owned by MassMutual, will primarily house functions that benefit from being located in a vibrant ecosystem with access to financial markets and digital talent.

The company also renewed its commitment to Springfield, where it was founded in 1851. It plans to make a $50-million investment in its State Street HQ campus facilities to accommodate 1,500 new positions by 2021.

MassMutual also plans to consolidate certain U.S. facilities in other parts of the country to its Springfield and Boston campuses in the not-to-distant future.